The study's purpose is to longitudinally evaluate four modalities of periodontal, therapy. Eighty-two human periodontal patients were originally treated with four different types of periodontal therapy in a split mouth design. The therapies were 1) coronal scaling and polish, 2) root planing, 3) modified Widman surgery, and 4) flap surgery with ostectomy to achieve positive osseous architecture. Presently seventy-four patients have completed two to four years of maintenance therapy. They are presently receiving examinations to ascertain their periodontal stability and mainte- nance care at three month intervals. Data are gathered documenting all clinical variables at yearly intervals. We propose to continue monitoring these patients and thereby to continue evaluating and comparing the longitudinal effects of the four periodontal therapy modalities. The clinical variables to be evaluated and compared are 1) probing depth, 2) probing attachment level, 3) incidence of probing attachment loss, 4) presence of gingival bleeding, 5) presence of gingival suppuration, 6) presence of supragingival plaque, 7) tooth mobility, 8) horizontal probing attachment level in furcations, and 9) furcation's open/closed status. Comparison of the response to therapy for two age groups will also be completed (< 38 yrs. and > 39 year olds).